350-501 Architecture Practice Question
A customer is experiencing intermittent packet loss in an MPLS L3VPN network. The PE routers show no errors on interfaces. Which tool can help isolate the issue by showing the complete path a packet takes through the MPLS network?
⚠ Common exam trap
Cisco often tests the distinction between MPLS ping (end-to-end LSP validation) and MPLS traceroute (hop-by-hop path discovery), and the trap here is that candidates confuse 'ping' with 'traceroute' and assume MPLS ping provides per-hop details, when it only confirms connectivity without revealing the intermediate path.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
MPLS traceroute
MPLS traceroute (often implemented via LSP ping with the 'traceroute' option or the 'mpls traceroute' command) is the correct tool because it uses MPLS echo request/reply messages (RFC 8029) to traverse the label-switched path (LSP) hop by hop, revealing the exact label stack and transit LSRs. This allows identification of a failing or misbehaving node in the MPLS core that standard IP traceroute would not see, since IP traceroute relies on TTL expiry in the IP header, which may not occur in an MPLS network where labels are swapped and IP TTL is often copied from the label TTL.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Traceroute
Why it's wrong here
Standard traceroute does not show MPLS labels.
- ✗
Ping
Why it's wrong here
Ping only tests end-to-end reachability, not the MPLS path.
- ✓
MPLS traceroute
Why this is correct
MPLS traceroute displays the label stack at each hop along the LSP.
- ✗
MPLS ping
Why it's wrong here
MPLS ping tests LSP connectivity but does not show the entire path.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 350-501 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 350-501 exam.